The Supreme Court today set a deadline of six months for CBI and ED to complete the probe in the 2G spectrum allocation cases and the alleged irregularities in FIPB approval to the Aircel-Maxis deal in which former finance minister P Chidambaram and his son Karti Chidambaram have been questioned by the agencies.

The issue of FIPB clearance in the the Aircel-Maxis deal had surfaced during the probe into the 2G spectrum related cases.

The top court said it is "very unfortunate" that investigation in the 2G cases has not been completed yet and "people of this country cannot be kept in dark in a serious and sensitive case like this".

A bench of Justices Arun Mishra and Navin Sinha, who were annoyed by the delay in completion of probe in the 2G spectrum cases, which started in 2010, said it will "haul every officer involved the case if investigation is not completed within next six months".

"Why is there so much delay in completing the investigation in the 2G spectrum and ancilliary cases. Investigation was ordered by this court in 2010 and since then several orders have been passed but nothing has happened so far. Tell us, how much investigation is pending and why have you not been able to complete the probe yet," the bench said.

The apex court questioned the Centre "whether there was any invisible hand" which was delaying the investigation of the case and directed that "investigation in all aspects has to be completed in the cases by next six months".

"This a very serious and sensitive case. You book everybody responsible in the case and investigation has to be completed in all aspects. We are unhappy the way things are going on as the investigation has not seen light of the day. This case is becoming like 'touch me not'," the bench said.

Attorney General K K Venuopal said that in the main 2G spectrum case involving the former telecom minister, the special court has acquitted all the accused and similarly in other related cases, the accused were either acquitted or discharged.

"Only in one case, investigation is still pending and this case relates to Aircel-Maxis case involving Malaysian business tycoon T Ananda Krishnan against whom letter rogatory have been issued but being an influential person in that country, we have not been able to bring him to India to face trial," Venugopal said.

He said Krishnan was not cooperating with the investigation in the case and no documents have been supplied by Malaysian government.

The bench said it was not concerned about the individuals or personalities involved in the case and the Centre should file a status report in two weeks with regard to investigation done so far.

The AG said the Centre will file the status report as per the court's direction and if the bench wants, then it will file the document without sealed cover notwithstanding the relationship with Malayasia government.

BJP leader Subramaniam Swamy said the court had in the last hearing directed CBI and ED to file the status report with regard to investigation done in Aircel-Maxis deal case.

"This status report which was to be filed in the court was unfortunately in the bedroom of one of the accused in the case," Swamy alleged, without taking any name.

The court also allowed a plea of senior advocate Anand Grover seeking to be relieved from his post as special public prosecutor in a case related to 2G spectrum case after recording words of appreciation for his efforts in the case.

It put a stamp of approval on the government's decision to appoint Additional Solicitor General Tushar Mehta as special public prosecutor in place of Grover for prosecution, appeals and revision of 2G related cases and dismissed a contempt plea filed by an NGO Centre for Public Interest Litigation.

On January 4 this year, the apex court had directed the Centre to file a status report on the probe being conducted in the Aircel-Maxis deal case. P Chidambaram was questioned by the CBI in the case on December 6, 2014, while Karti was questioned on November 19, 2014.

The CBI had said in its charge sheet in the Aircel-Maxis case that Chidambaram had granted FIPB approval in March 2006 to Mauritius-based M/s Global Communication Services Holdings Ltd, a subsidiary of Maxis, owned by Ananda Krishnan, who is also an accused in the case.

The CBI had claimed that M/s Global Communication Services Holdings Ltd had sought Foreign Investement Promotion Board (FIPB) approval for 800 million USD for which only the CCEA was competent, but Chidambaram had given approval to the firm in March 2006.

However, the CBI and ED cases in the Aircel-Maxis deal could not withhold judicial scrutiny as the special 2G court had in February last year discharged Dayanidhi Maran, his industrialist brother Kalanithi Maran and others saying the alleged charges were based on "misreading of official files", speculation and surmises of the complainant.